1. Field of the Invention
The present invention relates to a video detection cell having loop through functionality, and in particular to a video detection cell for sensing activity on a video line.
2. Discussion of the Related Art
Set top boxes are devices known in the art that can be connected to a television or other display monitor, and allow digital images to be viewed. In particular, a set top box comprises a microprocessor having a decoder for decoding a digital data stream, which is for example received by a cable connection, telephone line, network connection, or satellite. Such set top boxes generally comprise an interface for connecting to a television, which may be, for example, a SCART (Peritel) connection, and usually comprise further interfaces for interconnecting with other devices such as video cassette recorders, hard-disk recorders and DVD players/recorders, which may also be SCART connections.
The set top box may act as a routing means for connecting the television to these further devices, which are generally not connected to the television directly. Thus often, when using one of these devices, for example playing back a DVD or recording a video program to video cassette, the set top box itself is used solely for providing the interconnection, and not for decoding data. This function is known in the art as loop through. However, in order that such a box can provide loop through functionality, it is necessary for the set top box, and in particular the microprocessor, to be activated. This is disadvantageous for a number of reasons, for example due to the relatively high power that this consumes.